Unit heating system for baking ovens



May 5, 1953 c. KLEIN ETAL UNIT HEATING SYSTEM FOR BAKING ovENs Filed March 18. 1949 3 Sheets-Shea@l 1 May 5, 1953 c. KLEIN ETAT..

UNIT HEATING SYSTEM FOR BAKING ovENs 3 Sheets-Sheet 2 Filed March 18, 1949 May 5, 1953 c. KLEIN ETAL UNIT HEATING SYSTEM FOR BAKING ovENs 3 Sheets-Shea?I 3 Filed March 18, 1949 m Tm ,wma/ n @www n wmf y www B( uw @SHN ,q

.WMQLN Patented May 5, 1953 LTN SYSTEM, FDR BAKINQ. ,EZIFJBIES` AChris `lii'lein, k1Warrenville, 'Richard fC. 1-fSkariiun Afftilestern Snringafanol WilliamjG.'Tinkergfltasca,

lll.,;aassignors to'i'lhePeteirsenfvenompany. 'rFranklinaPariL-:Ill., a corporation;o'lllinois ipiilicatiorfMarch 18, 1949;'SerialNofSZM lthe'ovenandshipit to* the s-ite'vfor nal erection.

The" purpose of-sorproducing thevl ovens lhas been `1with' arveW-to "reduc-inet labor' in the field and facilitate l the nal `assembly of j parts, particularly in viewoffthe factf that theJ nature of the `mechanics 'in' the"""fi'eld` is general-ly `not of `such "form" as'tov permit'proper' and "e'icient operations :on variougsheet metal'fpartsand'components to take Kcare of-unforeseen olnoultiesat-l thesite-oi erection. Furthermoreysuch preassernbly ofthe foveniat the factory permits' testing to"a"li1nited "extent asf'to operation. v"netter"thiefnreasseinbly of the oven attheiactoryit iswknocked down `-an'd thevarious elementsfor' components arethen shipped toi thetsitefor final-assembly and-erecf'tion. L"Such practice inproducinecommercial 5vbakingrovens has Yresulted ingreat'consurnption Aof man" hours of time, as Well' aslr lheavy 'production costs.

The present inventionis directed 'to Vimprove-- "ments vin-'heatingsystems,` of the' indirect type, lforuse insuclr ovens. *Heretoforethe heating system l* for such ovens'ncmprisecl' ainultiplieity `of ductsy or conduitsv such-as Vpines-and other com- `nonents which are shipped' disassenlbleclV 'to the site' for 'nal---erection f Due to thenoneavailability ofproper equipment-and toolsat the-Siteof erection as compared Withy the-equipment land too-ls available in the'manuiacturing plant, there results'fa lgreat consumption -ofman hoursfin jproperly"V assembling the' elements -:in the; field, and which alsov necessitates expenditure of considerable'time in careful Atesting andchecking of the heating system for insuringproper functicning thereof.

One-of the `lcrimaryobjects of this invention is vtorprovide a prefabricatecl unitary heat exchanger,'forfan indirect; tyloeohh-eatingl system `of a baking ovenwhich 'isradaptedftol be produced "anclassembled-in nal'f-format the--factoryl for i insuring*uniformityr of production and construction and satisfactory performance.

Another object to provide a`y novel form of l heat exchanger for batting ovens,y produced asr a f prefabricated unitarystructure,V and i which-re --sults in substantial saving infinan hourslas-com- Lvpared vr"to conventionalmanuacturefand Yassemblyof such devices in tl1e"ield;

`Anrther object is to 'nrovide=a=novel heat-.exchanger4` unitf-for'an indirect-heating' systemy of a baking oven, formed' 4as aV `prefab'rica-ted; unitarir assembly and comprisinga-series of interconnectedv duct sections 'connected irl-series Arelationto orm'afcontinu- -=ous conduitythe free endof one ofthe duel-fseearrangeclfsideeby-sde and intertions vbeing formeelv iso-provide a'fchamber for a fluid fuel heater unit,- andthe other free end of ithe' duct system beingiformed to provide' a` housfing for @suction-blower, ancl'the 'chaniberv and the housingbeing interconnected by a riuot'section foi-effecting recirculation of aportion of i the heated-air in the system.

A still'urther object" isi toil provideI a prefabricated unitary heat exchangerlor an indirect Aheating system of` a lbaking-oven which is durable in construction, eicientfinoperation, and capable of Abeing economically manufactured.

Other-objects and advantages of this invention Willbe apparent fromvthe following description,

:take-n in connectionwitli the accompanying fdrawyfsysteni embodying? tlie-present invention;

Figure'Z-is: a `persrcnective View of the heat errlchanger'unit constituting the present invention;

f' Figure-3 `is a horizontal sectional View through :the 4vovenJshowine thellieatr exchanger in plan View;

'Figurea is an enlarged-vertical section through fthe #suction-blower -encl' of'y the heat exchanger, A takensubstantially as; indica-ted at '1ine= 4-'4 on Figure 1;

'Figure `isa sectionalview through the suctionblower housing, talienas Jindieateclat linee-# on f'lsigure '5 -is enlargedA verticalsection;y taken `substantially -in-:licatedwv at lineA on-flfigure l, showing =afheater unit-mounted Within the chamberecl'end'o the neat exchanger unit.

'In the-drawings, wehaVefsiioW-n the present n.ne-'etionwitlmother' types off-bakingovens. lvAs shown in the drawings, the oven comprises a walled enclosure deiining a baking chamber l0. The walled enclosure is Composed of four side walls il, a top wall I2 and a bottom wall i3. The front side wall is formed with a horizontally extending, elongated opening i 4 through which the materials to be baked are introduced into and when baked, removed from the baking chamber IG. The opening is adapted to be closed by a hinged door as indicated at i5.

The walls comprising the enclosure as shown in the drawings are each composed of a plurality of prefabricated unitary panel assemblies, as indicated at i'i, which are produced as complete components at the factory, and shipped to the site and assembled in the final erection of the oven, and thus serve to effect economies in production and assembly. The panel construction comprising the walled enclosure of the oven constitutes the subject matter of our co-pending application Serial No. 77,522, led February 21,

Mounted within the baking chamber i!) is a reel structure indicated at 2B, in dot and dash outline, comprising a plurality of circumferentially spaced apart trays 2i for supporting the material to be baked within the chamber ill. The total reel assembly is adapted to be rotated about a substantially horizontally extending axis, by suitable drive mechanism such as indicated generally at 22. In a reel type of oven it is to be understood that the material, as for example, foodstuffs, when positioned on the respective trays, travels in a circular path in the baking chamber for a predetermined period of time for effecting a proper baking operation thereon. In baking ovens as currently manufactured and sold, the heating systems, in the main, are of the indirect heat type, and generally employ hot air as the heating medium. Such heating systems include a series of ducts suitably arranged within the baking chamber, and the main heat transmitting ducts are usually located adjacent the bottom of the chamber.

The heating system of the present invention comprises a heat exchanger indicated generally at 2E, mounted adjacent the bottom wall I3 of the baking chamber. As may be seen in Figure 2 of the drawings, the heat exchanger is a prefabricated, unitary assembly comprising a plurality of duct sections 21, 28, 29 and 30 arranged side-by-side in substantially parallel, spaced apart relation, and the adjacent ends of the respective ducts are interconnected by end portions 32, 33 and 34 so that all of the duct sections are in series relation and constitute a continuous, sinuous conduit or duct, and the path of flow of hot air through the conduit is indicated by arrows in Figure 3 of the drawings. The duct sections in the main, as shown in the drawings, are of rectangular cross section, but may be of any other desired or convenient configuration. The duct section 2, at its free portion, merges into and constitutes a continuation of a chamber 38, herein shown as of cylindrical form, in which is mounted, when the heat exchanger is assembled in final position within the baking chamber, a iiuid fuel heater unit, indicated generally at 40. The fluid fuel heater unit, as shown in Figure 6 or" the drawings includes a ceramic lining 4| and suitable baiiles for the efficient combustion of gaseous fuels. In the event liquid fuel is to be employed, the heater unit may be of modified construction for insuring proper and eiiicient combustion, as is well understood in the art. The end of the chamber is closed by a plate 42 to which is attached a suitable nozzle head, indicated at 42a connected to a gas supply conduit 42h.

The free end portion of the duct section 30 merges into a housing 43 of a suction-blower unit. Said housing 43 and cylinder chamber 38 are interconnected by a duct section 45 for recirculating within the heating system a portion of the hot air of the system and thus insuring efficient operation.

The suction-blower housing also is provided with an upwardly extending duct section 41, which is connected to an upwardly extending vent or stack 48. Mounted within the vent duct or stack 48, as seen in Figure l of the drawings, is a suitable damper 50, adapted to be adjusted as desired for controlling the extent of spillage or discharge of the hot air from the heating system for assisting in controlling the temperatures of the baking chamber, as well as insuring efficient fuel combustion by the introduction of adequate fresh air into the heating system.

The end of the cylindrical chamber 38 is attached to plate 42 and the suction-blower housing 43 is attached to the end plates '60 by bolts as indicated at 52 and 53, respectively, passing through the side wall of the oven, as seen in Figures i and 6 of the drawings.

Positioned within the suction-blower housing is a vaned impeller element 55 having a tubular shaft 51 mounted in suitable bearings 58 carried on a supporting bracket 59, which is attached to the end panels 6s which serve as a closure for the outer end of the suction-blower housing, as clearly seen in Figure 4 of the drawings. The impeller is driven in a suitable manner and as shown in Figure 3 of the drawings by the drive arrangement indicated generally at 62.

The main portion of the unitary heat exchanger is preferably supported a short distance above the bottom wall of the oven chamber, and as seen in the drawings, said exchanger is supported on the corner edge of structural angle elements 65 and 66 with the cylindrical chamber 3S and blower-housing 43 and interconnecting du-ct 45 resting substantially upon the bottom wall of the baking chamber.

To protect the heat exchanger from damage in the event of excessive pressure being built up within the duct system, suitable pressure relief means is provided. As shown, pressure relief means are provided in the respective duct sections 23 and 30. Each pressure relief means comprises a frame formed or four pieces of metal tacked or secured to the duct in surrounding relation to an opening formed therein. The ring or frame secures in position in registration with the opening of the duct, a metallic plate i0 of considerably lighter gauge than the frame elements, and usually considerably lighter in gauge as compared to the material from which the ducts are formed, so that in the event of excessive pressure building up in the duct system, the light gauge plate 'iii will buckle to an extent that it is partially or totally withdrawn from the surrounding frame, and in the event of extremely great pressure such as may be caused by an explosion in the heating system, the plate may be blown out of the mounting frame.

As may be seen in Figure 3 of the drawings, the end portion 33 constituting the connection between duct sections 28 and 29 is disposed in spaced apart relation with respect to the connecting duct 45 between the suction-blower housing and the heat chamber 38 so as to permit a limited amount of expansion and contraction cf the respective duct sections without injury thereto. For convenience in shipment, however, it is preferred that the central duct sections be rigidly connected at their free ends and for this purpose, adjacent the corners of the connecting portion33 there is provided laterally extending lugs 'l2 extending in a position to cooperate with similar lugs i3, extending from the inner face cf the connecting duct E5. These pairs of lugs 'l2 and T3 are preferably bolted together initially to insure adequate rigidity of the total heat exchanger unit for purposes of shipment and handling, and the bolts are removed after the heat exchanger is installed in the baking charnber.

It will be apparent that by virtue of the present invention the unitary heating system for a baking oven may be quickly and easily placed in position within the baking chamber and connected in -place for nal assembly, requiring the expenditure of a relatively small amount of time, as compared to conventional practice, and thus ei'- fecting substantial economies in the erection costs of the oven, While at the same time insuring an eiiicient and satisfactory operating heating system.

Although we have herein shown and described a preferred embodiment of our invention, mani festly it is capable of modification and rearrangement of parts without departing from thespirit and scope thereof. We do not, therefore, Wish to be understood as limiting this invention .to the precise form herein disclosed, except as We may be so limited by the appended claim.

We claim as our invention:

In a baking oven having a walled enclosure defining a baking chamber, a unitary, prefabricated heat exchanger, adapted for mounting on the lower Wall of the chamber, comprising a plurality of longitudinally extending duct sections, including two outer sections and one or more intermediate sections arranged side-'byside in substantially parallel relation and interconnected at opposite ends in series relation to form a continuous conduit for the passage of heated air therethrough, the free end portion of one of the outer duct sections being formed as a chamber for the reception of a heater unit, and the free end portion of the other outer duct section being formed as a housing for a suctionblower, a separate duct interconnecting the heater chamber and the blower housing for recirculation of a portion of heated air passing through the heat exchanger, said separate duct extending transversely of and disposed adjacent to and. disconnected from the ends of the intermediate duct sections, and means for externally interconnecting said separate duct and the adjacent ends of the intermediate duct sections for stability in shipment and handling.

CHRIS KIEIN.

RICHARD C. SKARIN.

WILLIAM G. TINKER.

References Cited in the le of this patent UNITED STATES PATENTS Number Name Date 1,719,684 Besta July 2, 1929 1,852,526 Kemp Apr. 5, 1932 1,857,447 Engels May 10, 1932 2,041,930 Houlis May 26, 1936 2,138,465 Wundrack Nov. 29, 1938 2,556,840 Day June 12, 195i FOREIGN PATENTS Number Country Date 393,818 Great Britain June 15, 1933 

